<template>
  <div class="todo-footer" v-show="total">  <!-- 如果 total=0 则直接不展示 -->
    <label>
      <!-- <input type="checkbox" :checked="isAll" @click="checkAll"/> 使用 methods 方法实现 -->
      <input type="checkbox" v-model="isAll"/>
    </label>
    <span>
          <span>已完成{{doneTotal}}</span> / 全部{{total}}
        </span>
    <button class="btn btn-danger" @click="clearDone">清除已完成任务</button>
  </div>
</template>

<script>
  export default {
    name: 'MyFooter',
    props: ['todos', 'checkAllTodo', 'clearAllTodo'],
    computed: {
      doneTotal() {
        return this.todos.reduce((pre, todo) => pre + (todo.done ? 1 : 0), 0)
      },
      total() {
        return this.todos.length
      },
      isAll: {
        get() {
          if (this.total === 0) return false
          return this.doneTotal === this.total
        },
        set(value) {
          this.checkAllTodo(value)
        }
      }
    },
    methods: {
      /*checkAll(e) {
        this.checkAllTodo(e.target.checked)
      }*/
      clearDone() {
        this.clearAllTodo()
      }
    }
  }
</script>

<style scoped>
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>